Collapsible clothes drying racks have been known for well over a century, at least since U.S. Pat. No. 82,280 was issued to J. B. Blood on Sept. 22, 1868. As that patent was issued for an "Improved Clothes-Drier" of a complicated construction and specifically described dimensions, simpler and more conventionally designed collapsible clothes drying racks were presumably in use even earlier than 1868.
In the few cases known to applicant in which conventional collapsible clothes drying racks of "lazy tong" construction have been provided with extenders at their upper extremities, this has involved a complicated and relatively expensive arrangement of parts, such as in Cecil U.S. Pat. No. 3,133,645, issued May 19, 1964, and German Pat. No. 2,719,771 dated Nov. 24, 1977.
In some cases, such as the German patent just cited and Schissel U.S. Pat. No. 2,406,638 issued Aug. 27, 1946, flexible, spaced, parallel means have been provided to support the clothing being dried, which support means could perhaps be used to support a wet or damp sweater. However, if this was done, the sweater would dry in a distorted shape, and furthermore any such use would preempt all the hanging positions for other clothes to be dried.
It has long been known that the pivoted connections in the conventional lazy tong construction of a clothes drying rack tend to become loose with the passage of time, and with continued opening and closing of the collapsible racks. In fact, an almost universal complaint about conventional collapsible clothes drying racks that operate on the "lazy tong" principle is that as the pivoted connections become loose with extended use of the rack, the rack in its erected condition becomes so unstable that it often falls over, and the clothes being dried fall to the floor.
Fastening devices that would make it possible to adjust the pivoted joints of a collapsible clothes drying rack, to correct for this loosening that has occurred over time, have been used in such applications as disclosed in U.S. Pat. No. 521,861 issued to Zeiser et al. on June 26, 1894, almost a century ago. Similar devices have been used over the years in other applications, such as shown in German Pat. No. 2,420,264 dated Nov. 6, 1975. However, until applicant made the present invention, it has apparently not been thought possible to remedy the problem in question in collapsible clothes drying racks by utilizing such fastening means that have been available for a very long time in other fields.